Malabsorption & Chronic diarrhoea Flashcards
Diarrhoea - differential diagnosis (8 categories!)?
4 I’s and 4 M’s
Infection: bacterial, viral and parasitic (e.g. Giardia)
Inflammatory (IBD)
Intoleance - lactose / disaccharide (i.e. osmotic diarhoea)
IBS
Malabsorption (Coeliac, SBO, short bowel syndrome, pancreatic insufficiency)
Metabolic / Endocrine (diabetic autonmic neuropathy, hyperthyroidism)
Medication induced (e.g. Metformin)
Malignancy (CRC, Calcinoid, Villous adenoma)
Diarhoea investigations?
For 4 I’s
Stool culture, MCS, viral NAAT, OCP, C.diff.
Lactose tolerance test / lactose hydrogen breath test
ASCA/ANCA/Faecal calprotectin/Colonoscopy
For 4 M’s
Coeliac serology (TTG + IgA)
HBA1C, OGTT (if not known to be diabetic)
24h urine catecholamines & metanephrine (Phaeo)
24H urine 5-HIAA (Carcinoid)
TFT (Hyperthyroidism)
Finally colonoscopy to look for malignancy, IBD, microscopic colitis.
Symptom to ask about in taking history for patient with malabsorption? (5)
Steatorrhoea - offensive, bulky, pale stools
Weight loss
Skin rash (dermatitis herpetiformis - coeliac)
Symptoms of protein deficiencies - oedema
Symptoms of Minerals & Vitamin deficiencies (BDK):
- Anaemia (Iron def, B12 - megabloblastic)
- Glossitis (sore tongue), Angular stomatitis (red/swollen patches in the corners of the mouth) - Vitamin B def
- Peripheral neuropathy - Vit B12 or B1
- Bone pain (osteomalacia) - Vit D def
- Bruising (Vit K def)
Risk factors for malabsorption? (8)
Remember that coeliac disease, chronic pancreatiits and previous gastric surgery account for 60%
- Previous gastric syrgery/bowel surgery (e.g. ileal resection)
- Crohn’s disease
- Pancreatic & Liver disease - ask about ETOH
- FH of coleliac or IBD
- Radiation
- Drugs (cholestyramine)
- Diabetes
- HIV
Malabsorption examinaiton?
Inspection: cachexia, pallor, bruising, oedema, rash, TPN?
BMI (<20)
Hands: signs of CLD, pallor of palmar creases
Neck: lymphadenopathy (lymphoma a/w coeliac)
Eyes: pallor
Mouth: glossitis, angular stomatitis (B group def)
Abdo: scars (gastric surgery), splenomegaly (lymphoma in coeliacs)
Legs: PN (b12/thiamine def), Subacute combined generation of the SC
DDx for malabsorption (7+ causes)
Coeliac disease
Gastric / bowel surgery (e.g. ileal resection)
Chronic pancreatitis
GI disease: Liver disease, IBD, infection (e.g. Giardia)
Systemic disease: diabetes, HIV
Drugs: alcohol & cholestyramine
Radiotherapy
What is your approach to investigating malabsorption?
Demonstrate malabsorption
- Malabsorption “big 6”:
- Iron studies,↑INR, ↓Ca, ↓cholesterol, ↓carotene, +ve Sudan stain of stool for fat (good screening test for steatorrhoea)
- faecal fat estimation (over 3d) > 7g /d is abnormal (not widely available- alternative is faecal estalase) - greatly raised (>40g/d) strongly suggest pancreatic disease
- Glucose or lactulose breath hydrogen test (for SBO)
Evaluate consequences
- Anaemia: micro (iron), macro (B12), normo (chronic disease)
- Albumin, folate, B12, CMP, ALP
- Fat soluble vitamins A, D, E, K (INR)
Identify cause
- Coeliac screen: TTG, IgA, anti-endmysial Abs
- AXR: blind loops (SBO), pancreatic calcification
- CT pancreatic protocol/MRCP/EUS - chronic pancreatitis
- Gastroscopy + SB biopsy + duodenal aspirate for histology, parasites and bacterial growth → villous atrophy (coeliac), abnormal culture (SBO), clubbing + flattening of villi (Whipples), +ve PAS for macrophages (Whiples)
Investigation for malabsorption - gastroscopy + duodenal biopsies show subtotal villous atrophy. What are DDx other than coeliac disease? (5)
Tropical sprue (remember that TTG is also the most useful test for sprue)
Giardiasis
Lymphoma
Hypogammaglobulinaemia
Whipple’s (diarhoea, abdo pain, migratory non-deforming arthritis)
What is your approach to managing a patient with chronic diarrhoea & malabsorption?
Goals
- Treat the underlying disease
- Manage accompanying diarrhoea
- Correct nutrient deficits
- Optimise QOL
General managemen as follows.
Confirm dx & investigate for potential causes (A). Screen & treat depression.
T: Non-pharmacological
- Dietary changes: Avoid caffeine (no more than 1/d), sweatened drinks, fruit juices and sorbitol containing gums (worsens diarhoea due to osmotic effects, especially where patient has no colon or very short length.
- Fat restriction → reduces diarrhoea as unabsorbed FA induces secretory diarrhoea in colon
T: Pharmacological
- Medium-chain triglyceride (MCT) supplements (compensates for calories lost due to the dietary restriction)
- Fat-soluble vitamin supplements
- ORS to prevent dehydration
- Symptomatic treatment: loperamide
Involve dietician, seek Gastroenterology consult.
C: Screen for complications - regular DEXA to screen for metabolic bone disease & osteoporosis (fat malabsorption is risk factor) and fractures.
Disease specific tx
- Gluten free-diet (Coeliac)
- ABx (SIBO, Whipple’s)
- Cholestyramine / cholestipole (bile salt malabsorption)
What is the test of choice to screen for coeliac disease when patient have IgA deficiency?
DGP - serum IgG Deaminated Gliadin Peptide
How would you manage coeliac disease and how would you monitor the patient? (5)
Gluten-free diet (wheat, barley, rye) + education/counselling + Dietician
Pneumococcal vaccine (due to hyposplenism in coeliac)
Monitor TTG 3-6 months (should normalise)
Consider re-biopsy duodenum in 3 months to confirm histological healing
- Lack of healing/response may indicate alternative diagnoses or refractory sprue (which may respond to steroids) or lymphoma (T-cell enteropathy)
Osteoporosis screening
